Methods of making heat exchangers

ABSTRACT

A method of making a heat exchanger of the kind consisting of a stack of sheet metal pressings in face to face relation, adjacent pairs of pressings providing between them alternately channels for flow of coolant and spaces for flow of air, in which method the pressings are joined together by cold welding operations.

United States Patent Wolfe et al.

[451 Nov. 7, 1972 [54] METHODS OF MAKING HEAT EXCHANGERS [72] Inventors: John Anthony Bartlam Wolfe; John Edwin Frederick Clark, both of London, England [73] Assignee: Chrysler United Kingdom Limited England [22] Filed: March 2,1970

21 Appl. No.: 15,600

[30] Foreign Application Priority Data March 4,1969 GreatBritain ..l1,568/69 [52] US. Cl. ..29/157.3 D, 29/157.3 B, 29/470.1, 113/l18R,113/1l8D [51] Int. Cl. ....B2ld 53/00, B2lk 29/00, B23p 15/26 [58] Field of Search....29/l57.3 R, 157.3 D, 157.3 B, 29/4701; 113/118 R, 118 D; 165/166, 167

[56] References Cited I UNITED STATES PATENTS 2,790,628 4/1957 Barnes ..29/470.l X

Billetter ..29/470.1 X

2,874,942 2/ 1959 Rieppel et al ..29/470.1 X 3,071,216 l/1963 Jones et a1. ..29/470.l X 1,954,638 4/1934 Loeffler ..29/157.3 1,990,752 2/1935 Ragsdale ..1 13/118 D X 2,617,634 11/1952 Jendrassik ..165/140 3,451,114 6/1969 Werneke ..29/l57.3 7 3,512,238 5/1970 Canon et al ..113/118 X 3,537,165 11/1970 Paddock et al. ...113/118 D X FOREIGN PATENTS OR APPLICATIONS 1,007,886 10/1965 Great Britain ..29/157.3

Primary Examiner-John F. Campbell Assistant Examiner-Victor A. DiPalma Attorney-Mawhinney & Mawhinney [57] ABSTRACT A method of making a heat exchanger of the kind consisting of a stack of sheet metal pressings in face to face relation, adjacent pairs of pressings providing between them alternately channels for flow of coolant and spaces for flow of air, in which method the pressings are joined together by cold welding operations.

5 Claims, 7 Drawing Figures PATENTEDR V Hm 3,702,021-

SHEET 1 BF 4 I METHODS OF MAKING HEAT EXCHANGERS This invention relates to methods of making heat exchangers (e.g. radiators or oil coolers, for motor vehicle engines or car interior heaters or coolers) of the kind comprising a stack of pairs of sheet metal pressings in face to face relation, one set of adjacent pairs of pressings providing between them channels for flow of coolant and the other set of adjacent pairs of pressings providing between them spaces for the flow of air.

The invention provides a method of making a heat exchanger of the kind comprising a stack of sheet metal pressings in face to face relation, adjacent pairs of pressings providing between them alternately channels for flow of coolant and spaces for the flow of air, which method comprises joining pairs of pressings which provide between them channels for flow of coolant by cold welding and joining the thus formed pairs by cold welding to provide the spaces for flow of air.

' The cold welding of each pair of pressings and of the pairs of pressings may be carried out in a number of cold welding operations at adjacent locations.

The cold welding operations may be carried out at overlapping locations.

A fin or fins may be secured to the pressings in each air space.

Prior to the cold welding of the pressings to form pairs, a fin of wave or zig-zag form may be welded at alternate crests to the side of each pressing which bounds an air space.

,The crests of the fins may be cold welded to the pressing.

The crests of the fins may be resistance welded to the pressing.

The welding operation of the crests of a fin to a pressing may form a groove in the pressing in which the crest is located, which groove serves to stiffen the pressing.

The fins may be located on the pressings so that crests on the tins of adjacent pressings abut one another.

Preferably each pressing has two spaced depressions having openings in the bottom thereof, a channel connecting the two depressions and a peripheral flange extending along either side of the channel and around the depressions in which case pairs of pressings are first assembled with their flanges in face to face relationship, the flanges are cold welded together and the resulting pairs of sheets are assembled with the spaced depressions on one side of one pair of sheets in engagement with the spaced depressions on one side of another pair of sheets so that the openings in the engaging depressions communicate with one another, and the depressions are then cold welded together.

The following is a description of two embodiments of the invention reference being made to thezaccompanying diagrammatic drawings in which:

FIG. 1 is a perspective view of one of the aluminum pressings which make up the radiator having a length of finning secured thereto;

FIG. 2 is a sectional view showing the finning and pressing in spaced relationship;

FIG. 3 is a side view of the pressing and finning;

FIG. 4 is a perspective view of two pressings secured together;

FIG. 5 is a side view of the joined pressing shown in FIG. 4;

FIG. 6 is a sectional view of two pairs of pressings being joined together by a mandrel tool; and

FIG. 7 is a sectional view on the line 7-7 of FIG. 6 with the mandrel removed.

Referring firstly to FIGS. 1 and 2 of the drawings one end of an aluminum sheet pressing 10 is shown having a depression 11 adjacent one end thereof the bottom 12 of which has an opening 13. A similar depression (not shown) is formed at the other end of the pressing and a channel 14 extends between thev depressions. The pressing has a peripheral flange 15. A fin is secured to the outside surface of the channel 14 between the depressions l l a part of the tin being illustrated in FIG. 1 and comprising an aluminum strip 16 which is bent into wave form. The crests 17 of the waves of the strip which engage the surface of the channel 14 are cold welded to the channel by pressure inthe direction of the arrows 18 in FIG. 3. The channel is supported on the inside thereof in a manner which permits the pressure used in the cold welding to form grooves indicated at 14a in FIG. 6 extending across the channel in which the crests 17 of the strip are secured. In an alternative method the fins may be resistance welded to the channels 14. The strip 16 is formed with spaced louvres 19 to permit air flow through the sheet. 1

Referring now to FIGS. 4 and 5 of the drawings two pressings 10 are shown assembled with their respective flanges in face to face relationship and the flanges are cold welded together along the line 20 by a press tool (not shown) to provide a watertight joint between the flanges. The cold welding may be carried out in a single operation or, more conveniently, lengths of the flanges may be welded together at overlapping locations until the flanges are welded together around their entire peripheries. a

Referring now to FIGS. 6 and 7 of the drawings the assembly of two of the units is shown the units being placed with the depressions of the plate of one unit in engagement with the depressions of a plate of the other unit and the openings of the depressions in register. The depressions are cold welded together around their openings by a mandrel tool 21 having three spaced pairs of jaws around its circumference. The jaws are radially movable and are withdrawn to permit the mandrel to be inserted through the openings. The jaws 22 are then expanded to engage on either side of the depressions and are closed to cold weld the parts of the depressions engaged by the jaws together. The jaws extend over segmental parts of the bottoms of the depressions and when one set of segments indicated at A, C and E in FIG. 7 has been cold welded by the jaws, the mandrel is rotated and a further set of segments indicated at B, D and F which partly overlap the first set are cold welded. The jaws 22 are then retracted to permit the mandrel to be withdrawn from the depressions. As shown in FIG. 6 the depth and location of the bent strips 16 is such that the crests of the strips which are spaced from their respective sheets abut one another. Further units are then secured to the two units formed in this manner until a stack of the required capacity has been formed.

In all the cold-welding operations referred to above pressures of the order of ton/sq. inchare used.

The communicating depressions on either side of the stack provide header pipes for connection to supply and return conduits and the channels provide passages for coolant flow between the header pipes in the case of a down flow heat exchanger. Alternatively the communicating depressions provide side pipes fora cross-flow type heat exchanger. v

The heat exchanger is particularly suitable for use as a radiator in a coolant system for a motor vehicle -engine.

What is claimed is:

l. A method of making a heat exchanger of the kind comprising a stack of sheet aluminum orv aluminum alloy pressings'in face to face relation, each pressing having two spaced depressions each provided with an opening in the bottom thereof, a channel connecting the depressions and a peripheral flange, which method comprises the steps of:

a. locating fins of wave form having spaced crests on each pressing on the outside'of the channel thereof with certain crests of the waves abutting the channel and the remaining crests spaced from the channel;

b. internally supporting the channel;

c. applying pressure to those crests abutting the channel to cold weld the crests to the channel and at the same time "to" form grooves in the channel which receive said crests;

-d. assembling pairs of'the pressings in face to face relation with the peripheral flanges of the pressings abutting one another;

e. cold welding the peripheral flanges together;

f. assembling thepairs of pressings together with the depressions of adjacent pressings in engagement and said remaining crests of the fins of adjacent pressings in-engagement with one another; and,

g. cold welding said depressions together.

2. A method as claimed in claim 1 wherein the cold welding of each pair of depressions and of each pair of abutting peripheral flanges is carried out in a series of cold welding operations at adjacent locations.

3. A method as claimed in claim 1 wherein the cold welding of each pair of depressions and of each pair of peripheral flanges is carried out in a series of cold welding operations at overlapping locations.

4. A method as claimed in claim 1 wherein the crests of the fins are cold welded to the pressing.

5. A method as claimed in claim 4 wherein the fins are located on the pressings so that crests on the tins of adjacent pressings of each pair abut one another.

It a n: a a 

1. A method of making a heat exchanger of the kind comprising a stack of sheet aluminum or aluminum alloy pressings in face to face relation, each pressing having two spaced depressions each provided with an opening in the bottom thereof, a channel connecting the depressions and a peripheral flange, which method comprises the steps of: a. locating fins of wave form having spaced crests on each pressing on the outside of the channel thereof with certain crests of the waves abutting the channel and the remaining crests spaced from the channel; b. internally supporting the channel; c. applying pressure to those crests abutting the channel to cold weld the crests to the channel and at the same time to form grooves in the channel which receive said crests; d. assembling pairs of the pressings in face to face relation with the peripheral flanges of the pressings abutting one another; e. cold welding the peripheral flanges together; f. assembling the pairs of pressings together with the depressions of adjacent pressings in engagement and said remaining crests of the fins of adjacent pressings in engagement with one another; and, g. cold welding said depressions together.
 2. A method as claimed in claim 1 wherein the cold welding of each pair of depressions and of each pair of abutting peripheral flanges is carried out in a series of cold welding operations at adjacent locations.
 3. A method as claimed in claim 1 wherein the cold welding of each pair of depressions and of each pair of peripheral flanges is carried out in a series of cold welding operations at overlapping locations.
 4. A method as claimed in claim 1 wherein the crests of the fins are cold welded to the pressing.
 5. A method as claimed in claim 4 wherein the fins are located on the pressings so that crests on the fins of adjacent pressings of each pair abut one another. 